In general, a footwear last used for manufacturing a shoe should endure a high pressure and a high heat. Thus, the footwear last is manufactured using an aluminum mold. Highly priced, the footwear last is highly burdened in economy. Metallic, it causes an impact and a noise and in addition, has a difficulty in its manufacture. Heavy in weight, it has a difficulty in treatment.
A conventional plastic last is formed of polyester to solve such a drawback. However, the convention plastic last is not only deformed during a longtime use because of a heat generated in a heating process, but also it causes an inconvenience in that it should be molded in about a double size of a real thing and then, be cut and processed in its manufacture. Further, its recycle is insignificant for the reason of economy and thus, environmental pollution occurs.
A conventional method for manufacturing the plastic last will be briefly described with reference to FIGS. 1A to 1I below.
Referring to FIGS. 1A to 1I, the conventional method includes molding a polyester raw material, cutting (roughing and finishing), finishing both toe and heel ends, painting, a color maker pin process, a stainless pipe process, and checking.
After the injection molding of the polyester raw material, as shown in FIG. 1A, the polyester raw material is roughed such that it has a length and a body-around size larger than a finished last by 10 mm to 15 mm and 30 mm to 35 mm, respectively. After that, as shown in FIG. 1B, the roughed polyester raw material is finished. The finishing is based on” last dimension chart”, and is performed according to bottom, toe, and heel gauges and a stick length.
After that, as shown in FIGS. IC and 1D, toe cutting is performed according to the toe gauge and then, heel cutting is performed according to the heel gauge. Next, the heel pin and stainless pipe processes are performed. As shown in FIG. 1E, the heel pin process is a process of driving five heel pins of Ø2.5 at an interval of 5 mm in a straight line, using a drilling machine of Ø2.5. As shown in FIG. 1F, the stainless pipe process is a process of driving a stainless pipe of 12.7Ø to a top surface of the last.
As shown in FIG. 1G, it is checked whether or not the bottom gauge is matched with a toe bottom line. As shown in FIG. 1H, a toe and a heel are checked. As shown in FIG. 1F, the toe and heel of the last are adapted to a front and a rear of a caliper diameter for callipering the length of the last and then, the last is measured in length.
The conventional method has the above many problems. In addition, the conventional method has disadvantages, in particular, that it has a difficulty, needs a long time, and highly costs in manufacture. In addition, because of a grinding work for the processed heel and toe, a worker should check a gauge by manual one by one. Because of a non-uniform work, an accurate and delicate curved surface of the heel cannot be kept.